In networks that utilize copper pairs, also referred to as metallic loops or twisted wire pairs, baseband telephony services and DSL services are often provided over the same copper pair. In these types of networks, transients associated with baseband ringing used to signal incoming call requests can result in the occurrence of bit errors data being transmitted with DSL technology. Most if not all DSL systems are susceptible to such transients.
Plain old telephone service (POTS) filters or splitters are widely used to separate the baseband telephony services, which occupy lower frequencies (i.e., typically below about 4 kilohertz (kHz)), from the higher data frequencies associated with DSL services. POTS filters normally filter out signals above about 20 kHz so that noise in the baseband does not adversely affect the DSL transmissions. However, even where POTS filters are utilized, it has been determined that periodic transients are sufficiently powerful to couple from adjacent wires resulting in impulse noise and bit errors in data being transmitted at the higher DSL data rates. DSL communications equipment may also employ powerful block codes and interleavers to disperse the transient. These methods have undesirable complexity and result in significantly slower data transmission rates. Accordingly, a need exists for a method and apparatus for reducing the number of bit errors that occur as a result of periodic transients in DSL data transmission.